One Pager Cheat Sheet

• In this lesson, we will learn about database transactions and isolation levels, understanding the read phenomena and key points in database systems.
• SQL (Structured Query Language) is highly popular and is widely used among developers and companies to create, modify, and query relational databases in an efficient and intuitive manner.
• To perform operations on database tables, we execute a SQL query.
• Transactions commits or rollbacks performed reads and writes of values in the database, thus ensuring that any single operation is a collection of several smaller ones.
• Multiple transactions executing simultaneously can cause inconsistencies in the database, which can be prevented by the ACID properties, with a special emphasis on isolation.
• Concurrent transactions can lead to Dirty Read, Non-repeatable Read and Phantom Read issues when accessing the same resource at the same time.
• The results of a transaction are either committed permanently, or rolled back if unsuccessful.
• We are discussing Isolation Levels, which dictate how much a certain transaction needs to be isolated from other transactions in a SQL database system.
• Using varying isolation levels, you can choose to either allow or prevent Dirty Reads, Non-repeatable Reads, and Phantom Reads.